Eyebolt assemblies and swivel shackle assemblies have been used for many years in conjunction with cables and a hoist to lift and move heavy objects about the workplace, such as dies, molds, heavy castings, etc. The swivel shackle assemblies typically include a "U" shaped shackle member that is pivotal on a swivel body that in turn is rotatable about an axis on a base that is perpendicular to the swivel axis of the shackle on the base. This enables the shackle to accommodate two axes pivotal movement which is necessary for the geometry of the hoist arrangement.
In a typical hoist arrangement, an overhead crane has a depending single cable that is tied to four (more or less) outwardly extending cables connected to the eyebolts or shackle assemblies. Each eyebolt or shackle assembly typically has a threaded fastener extending centrally there-through that bolts the shackle directly to the top surface of the die or mold.
The following patents are representative of the prior art relating to dual axis hoist fastener assemblies.
The Andrewe, et al., U.S. Pat. No. 3,297,293, issued Jan. 10, 1967; the Tsui, et al., U.S. Pat. No. 4,705,422, issued Nov. 10, 1987; and the Chandler, U.S. Pat. No. 5,352,056, issued Oct. 4, 1994, all show swivel shackle assemblies having a "U" shaped member or shackle that is pinned to a rotary swivel member by transverse pins that are separate from the "U" member itself. In this design, it is necessary to fix these shackle pins in the swivel body.
A second group of patents represented by the Wong, et al., U.S. Pat. No. 4,570,987, issued Feb. 18, 1996; the Tsui, et al., U.S. Pat. No. 4,641,986, issued Feb. 10, 1987; and the Tsui, et al., U.S. Pat. No. 5,405,210, issued Apr. 11, 1995, show hoist swivel shackle assemblies in which the ends of the "U" shaped shackle extend radially inwardly and form the pivotal bosses for the shackle on the swivel body member.
The Mueller, U.S. Pat. No. 3,492,033, discloses a clevis assembly with a locking ring 48 for locking the stud to the load.
The Brawand, U.S. Pat. No. 3,163,901, shows a cargo hook and chain device in which a line holder 14 is detachable from member 10 and adapted to hold one or more load cables 16. The line holder 14 has an arcuate slot that permits its removal from a swivel-type draft line terminal member 10.
The Blatt, U.S. Pat. No. 3,628,820, shows a side pull type swivel-type hoist ring assembly in which the hoist ring is generally perpendicular to the axis of the shoulder screw 28.
The Bateman, U.S. Pat. No. 1,321,356, shows an anchor shank and shackle in which the shackle itself is removable from the anchor shank 9.
The Jergens Manufacturing Co. makes a line of side pull style hoist rings identified as part numbers 47311 to 47319 that have extra-large diameter rings and generally U-shaped swivel members.
In addition to swivel shackle assemblies, eyebolt assemblies have been utilized in similar material handling applications. The eyebolt includes a threaded stud that is threaded into the load and the conveyor cable system usually includes a hook-type element that is connected to the eye of the eyebolt for lifting and conveying the load. Eyebolts have a significant advantage over swivel shackles because they are substantially lower in cost.
Because the eyebolt assemblies have no rotational movement as do swivel shackles, it is necessary that they be rotated so that the eye of the eyebolt assembly is in the same plane as the cable hook and cable. However, this has been found difficult to achieve because once the eyebolt is tightened to the maximum torque, further rotation, in an effort to place the plane of the eye in the same plane as the cable, causes over-torquing frequently resulting in failure of the threaded stud, which of course goes into tension as the eyebolt is torqued, usually done with a steel pipe through the eye. The other alternative to achieve angular orientation of the eye of the eyebolt is to torque the eyebolt to its maximum torque and then back off until the eye is rotated to the desired plane, but this results in the eyebolt becoming loose, which shortens eyebolt life span when utilized with a heavy load and overhead conveyor system and creates a hazard to workers and operators, so the present invention also reduces operator anxiety.
A further problem is that over-torquing to achieve the desired eyebolt angular orientation causes galling and deformation of the washer between the eyebolt and the face of the load.
It is a primary object of the present invention to ameliorate the problems noted above in load carrying hanger assemblies.